Engine Company #3 was organized in 1832 in quarters at 251Cambridge St, near 4th Street. The company at this time was named Niagara 3 and was equipped with a Thayer hand engine. On 18 September 1862, a new Amoskeag 400 gpm horse-drawn steamer was placed in service and a Hunneman horse-drawn hose carriage also was placed in service. Engine 3 became the first horse-drawn company in the city.

On 4 January 1871, the company moved to new quarters at 40 Fourth Street, between Cambridge St. and Gore St. This building also housed Police District Station #1. On 19 Jan. 1872, a new Amoskeag 600 gpm steam pump was placed in service. On 24 March 1886, a new 4-wheel hose wagon was placed in service by the company.

Engine 3 relocated to new quarters on Third St., near Otis St. on 1 March 1893. On 31 Jan. 1896, the company again moved to new quarters at 35 Third St., at the corner of Gore St. The previous Third St. firehouse was razed for construction of the Middlesex County Court House complex.

In October of 1919, an American LaFrance type 31 tractor was placed under the 1872 steamer and an American LaFrance hose and chemical wagon was placed in service as the wagon. In 1925, a new American LaFrance 750 gpm pump was placed in service by Engine 3.

In July of 1949, a new GMC/Robinson hi-pressure fog/hose wagon was placed in service. In November of the same year, a new Pirsch 1000 gpm pump was delivered and placed in service by the company. A new International/Farrar hose wagon was placed in service in July of 1966. In 1970, the 1949 Pirsch pump was placed out of service. From 1970 until 1977, Engine 3 ran with a series of spare and auxiliary pumps.

On 13 March 1977, a new Pirsch 1250 gpm/foam pump was placed in service. On 18 Sept. 1978, Engine 3 moved to new quarters with Truck 2 at 173 Cambridge Street. On 1 Dec. 1982, Engine 3's hose wagon was reassigned to Engine 9. Engine 3 now became a single unit company. In July of 1998, the current 1998 Pierce Saber foam pump was placed in service.